<!DOCTYPE HTML>
<html>

	<head>
		<meta charset="UTF-8" />
		<title>pro.html</title>
		<style type="text/css">
			.checkCode {
				cursor: pointer;
				/*border: 1px solid black;*/
				text-align: center;
				line-height: 26px;
				width: 115px;
				height: 35px;
			}
		</style>
		<script type="text/javascript">
			var sleep = 30,
				interval = null;
			window.onload = function() {
				var btn = document.getElementById('btn');
				btn.onclick = function() {
					if(!interval) {
//						this.style.backgroundColor = 'rgb(243, 182, 182)';
						this.disabled = "disabled";
						this.style.cursor = "wait";
						this.value = "重新发送 (" + sleep-- + ")";
						interval = setInterval(function() {
							if(sleep == 0) {
								if(!!interval) {
									clearInterval(interval);
									interval = null;
									sleep = 30;
									btn.style.cursor = "pointer";
									btn.removeAttribute('disabled');
									btn.value = "免费获取验证码";
									btn.style.backgroundColor = '';
								}
								return false;
							}
							btn.value = "重新发送 (" + sleep-- + ")";
						}, 1000);
					}
				}
			}
		</script>
	</head>

	<body>
		<input class="checkCode" type="button" id="btn" value="免费获取验证码" />
	</body>

</html>